1. The Field of the Invention
This invention relates to hernia repair and more particularly to apparatus and methods for expanding and maintaining the shape of hernia patches during hernia repair.
2. The Background Art
With more than 20 million hernia repairs occurring worldwide on an annual basis, hernia repair is the most frequently performed surgical operation in the world. Although there are many different techniques for repairing hernias, these techniques generally can be classified as either tension or tension-free repairs.
For many years, tension repair was the primary procedure used to treat people with hernias. Using this techniques, an incision is generally made in the abdomen over the hernia site. Any protruding tissue is pushed back into the correct position within the abdominal cavity and the hernial defect is mended with stitches or sutures. Because the stitches or sutures generally exert tension on the sides of the defect in order to keep it closed, this technique may cause more pain and discomfort than other repair techniques and there is typically a higher probability that the hernia will recur. Consequently, this technique is generally only suitable for very small hernias.
Tension-free repair techniques are currently the most common techniques and generally utilize a piece of mesh to bridge the hernial defect. These meshes are typically constructed of synthetic materials, such as Goretex®, Teflon®, Dacron®, Marlex®, Prolene®, or the like. Tension-free repairs may be performed using either open surgery or laparoscopic techniques. In open surgery, a surgeon usually makes an incision over the hernial defect and folds and inserts a mesh patch through the incision. This patch may be manually unrolled and positioned inside the abdomen before being fastened with staples, sutures, or the like to the abdominal wall over the defect. Once the mesh is securely attached, tissue grows through the mesh to create a strong but flexible layer that mimics the abdominal wall.
Tension-free mesh repairs may also be performed laparoscopically. Using this technique, a mesh patch is usually folded and inserted into the abdomen through a small incision away from the hernial defect. The patch is then moved to the region of the hernia, unfolded, positioned over the defect, and attached to the abdominal wall. This surgery is generally referred to as posterior hernia repair because the hernia is repaired from behind the abdominal wall.
One challenge in performing both open surgery and laparoscopic mesh repairs is unfolding and positioning a mesh patch inside the abdomen once inserted. Because there is typically very little room to work and visibility may be limited inside the abdomen, it is often difficult or awkward to unroll and position a mesh patch prior to attachment. This may result in a patch that is undesirably creased or poorly positioned, creating unwanted tension or discomfort within the abdomen. As a result, some manufacturers of mesh patches have integrated devices, such as “memory recoil rings” into their patches to allow them to spring open and lie flat once positioned inside the abdomen. These recoil rings are flexible enough to be rolled or folded tightly to allow insertion through an incision in the abdomen.
Nevertheless, these recoil rings may also be prone to break under the stress of folding, rolling, or placement inside the intra-abdominal space. In fact, several different models of patches from at least one manufacturer have been recalled due to instances of breakage inside the abdomen. These breaks can cause various problems, such as bowel perforations or chronic intestinal fistulae (i.e., abnormal connections or passageways between the intestines and other organs).
In view of the foregoing, what is needed is a mesh patch that is easily unfolded and positioned within the abdomen, while reducing the safety concerns associated with patches using recoil rings or other expansion mechanisms. Ideally, an improved expansion mechanism should be incorporated into a mesh patch and left inside the abdomen after closing the incision. Furthermore, such a patch would ideally be useful in both open surgery and laparoscopic procedures.